JPH0656824B2 - Chip-shaped electronic component and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-shaped electronic component such as a chip inductor, a chip capacitor, an LC composite chip component and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a chip-shaped electronic component is composed of an electronic component main body and a pair of external electrodes formed outside the electronic component main body. The electronic component body is formed by alternately laminating ceramic sheets and conductive paste and sintering the same, and the external electrode is formed of a dense metal body obtained by applying the conductive paste to the outside of the electronic component body and baking it.

By the way, when the external electrodes are formed on the electronic component main body, as shown in FIG. 2, the conductive paste (external electrode) 1 shrinks in the direction of arrow A along with the baking, and a part of the electronic component main body 2 is not covered. A uniform stress may act, and a crack 3 may occur in a part of the electronic component body 2.

Further, when the electronic parts are soldered to the substrate, if the external electrodes are dense, as shown in FIG. There may be a case where a crack 3 is generated in a part of the electronic component main body 2 due to a non-uniform stress acting on a part of the electronic component main body 2 directly through the.

Therefore, recently, as shown in FIG. 4, the external electrode 1 formed on the outer side of the electronic component body 2 is attached to the porous metal body 5.
In order to prevent cracks from occurring in the electronic component body, the stress acting non-uniformly on the electronic component body 2 during baking or soldering is alleviated.

[0006]

However, if the external electrode is made porous, the plating solution penetrates into the external electrode when electroplating the external electrode, and a small amount of this plating solution remains after washing with water. There is a problem that this corrodes the external electrodes and causes poor conduction. An object of the present invention is to provide a chip-shaped electronic component which does not exert uneven stress on the electronic component main body at the time of external electrode formation or soldering, and which has high external electrode corrosion resistance, and a manufacturing method thereof. To do.

[0007]

A chip-shaped electronic component according to the present invention comprises an electronic component main body and a pair of external electrodes formed outside the electronic component main body, and the external electrodes are impregnated with a synthetic resin. And a plating layer formed on the outside of the porous metal body.

Further, in the method for manufacturing a chip-shaped electronic component according to the present invention, a pair of external electrodes made of a porous metal body is formed on the outside of the electronic component body, and the external electrodes are impregnated with a synthetic resin, and the external electrodes are impregnated. The synthetic resin on the surface of the electrode is removed, and the surface of the external electrode is electroplated.

Here, the chip-shaped electronic parts refer to chip inductors, chip capacitors, LC composite chip parts, and other chip-shaped electronic parts. Further, as the synthetic resin with which the external electrode is impregnated, silicone resin, epoxy resin, phenol resin and other synthetic resins can be used. Impregnation of the external electrode with the synthetic resin is performed under reduced pressure.

[0010]

In the present invention, since the external electrode is made porous, the stress acting on the electronic component body during firing or soldering is relaxed, and non-uniform stress does not act on the electronic component body. Further, in this invention, since the external electrodes are impregnated with the synthetic resin, when the external electrodes are electroplated,
The plating solution does not enter the external electrodes.

[0011]

Example 1 First, ceramic sheets and conductive paste are alternately laminated and sintered to form an element body that is an electronic component body, and the conductive paste is applied to both ends of the element body. The laminated chip inductor was obtained by baking at ℃. Here, the conductive paste used had the following composition. Ag particles (spherical particles, average particle size 0.5 μM) 73 wt% Glass frit (ZnO-B ₂ O ₃ -SiO ₂ ) 4 wt% Ethyl cellulose ...................................... ………… 10wt% (1: 1) mixture of butyl carbitol acetate and ethyl carbitol …………………………………… 13wt%

Next, a silicone resin solution diluted with toluene is put in a container, a laminated chip inductor is put in this silicone resin solution, this container is put in a decompression container, and the pressure is reduced to about 1 torr by a vacuum pump. The state was maintained for about 10 minutes. By this treatment, the silicone resin liquid was impregnated into the external electrodes.

Next, this multilayer chip inductor was taken out of the container and heated at 200 ° C. for 1 hour. By this heating, the silicone resin impregnated in the laminated chip inductor was cured.

Next, this laminated chip inductor was placed in a rotary barrel, and the synthetic resin adhering to the surface of the external electrode was removed. Then, the external electrodes were electroplated, washed with water to remove the plating solution, and finally dried in a dryer.

Next, the multilayer chip inductor was cut so that the external electrode was included, and the cross section of the external electrode was observed with a microscope. As a result, as shown in FIG. 1, the silicone was filled in the pores of the porous metal body 5. It was observed that the resin 6 was impregnated and the plating layer 7 was formed on the outside thereof.

Next, 100 of these laminated chip inductors were placed in a humidity resistant tank, and the temperature was set to 85 ° C. and the humidity was set to 95%.
When left standing for 00 hours and then taken out and examined for electrical continuity between external electrodes, no electrical continuity failure was found.

Comparative Example 1 Next, 100 laminated chip inductors before the external electrodes were impregnated with silicone resin in Example 1 were electroplated, washed with a plating solution and dried, and then Example 1 was used.
A moisture resistance test was performed under the same conditions as in 1., and when taken out and examined for a conduction state between the external electrodes, 77 pieces were defective in conduction. Further, when the cross section of the external electrode of this multilayer chip inductor was observed, as shown in FIG. 5, many corroded portions 8 were formed in the plated layer 7.

[0018]

Industrial Applicability The present invention provides a chip-shaped electronic component provided with an external electrode having high corrosion resistance, in which non-uniform stress does not act on the electronic component body when forming the external electrode or soldering. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of external electrodes of a multilayer chip inductor according to a first exemplary embodiment.

FIG. 2 is an explanatory diagram showing a state in which an external electrode that shrinks by firing exerts non-uniform stress on an electronic component body.

FIG. 3 is an explanatory view showing a state in which the solidifying and contracting solder exerts a non-uniform stress on the electronic component body via the external electrodes.

FIG. 4 is an enlarged cross-sectional view of an external electrode made of a porous metal body.

FIG. 5 is an enlarged cross-sectional view showing how the plated layer of the external electrode made of a porous metal body is corroded.

[Explanation of symbols]

 1 External Electrode 2 Electronic Component Body 3 Crack 4 Solder 5 Porous Metal Body 6 Silicone Resin 7 Plating Layer 8 Corrosion Part

Claims (2)

[Claims] 1. An electronic component main body, and a pair of external electrodes formed outside the electronic component main body, the external electrodes being impregnated with a synthetic resin, and a porous metal body outside the porous metal body. A chip-shaped electronic component comprising a plating layer formed on the. 2. A pair of external electrodes made of a porous metal body is formed on the outside of the electronic component body, the external electrodes are impregnated with a synthetic resin, and the synthetic resin on the surface of the external electrodes is removed. A method for manufacturing a chip-shaped electronic component, which comprises subjecting a surface to electroplating.